Interior lights or interior lighting devices are provided for internal spaces, there being a wide variety of subtypes. It is common to interior lights that they are generally rigidly mounted, for example on a wall, in a shelf, in a display case on a pedestal or the like. They are designed to be connected to a conventional domestic mains supply.
In interior lights, increased requirements are regularly placed on the design or the external appearance.
Shop downlights or ceiling downlights are one subtype of interior lights. They may be provided for mounting in busbars which are attached to a ceiling and which simultaneously mechanically hold the downlights and make power supply possible. A further subtype of interior lights are specifically provided for shelf or display case lighting. Interior lights of this type are generally of a very compact or small construction.
In shelf or display case illumination, a particular requirement is that of showcasing a product item or a portion of a product shelf using light specifically directed onto it, for the purpose of presenting of a product. In particular, it should be possible to shine light onto individual regions selectively, the surface to be illuminated having a predetermined size or outline. It is thus expedient to limit the beam angle of the light. On the other hand, however, interior lights of this type for shelf or display case lighting should also be usable for different goods or on different presentation stands. It is therefore particularly advantageous to provide a corresponding interior light with a variably adjustable beam angle. Thus, it is also possible in particular to make a subsequent change to the desired light situation or to reuse an interior light for a newly constructed presentation situation in spite of different requirements on the beam angle.
EP 2 221 524 A3 discloses an LED light in which the distance between the LED and a lens is adjustable. For this purpose, the LED light has a rotational adjustment arrangement, which consists of a guide groove, extending in a helical line shape about the longitudinal axis of a two-part housing, on a first housing part and a peg, guided in the guide groove, on a second housing part. By rotating the two housing parts with respect to one another, the distance between the lens and the LED in the axial direction can be adjusted. In an LED light of this type, the desired beam angle has to be set by trial and error. Furthermore, the second housing part is arranged externally around the first housing part, and has, by comparison with the first housing part, a rather large diameter which in particular opens out in a funnel shape and so the light as a whole has a comparatively large diameter.